1. Field of the Invention
The present invention relates to a mechanism for mounting a seat belt of a center seating space of a vehicle seat, which exhibits sufficient strength while allowing for the greatest degree of reduction both in its weight and production costs.
2. Description of the Related Art
A Japanese Utility Model Application Laid-Open No. HEI 2-143252 discloses a mechanism for mounting a seat belt of a center seating space of a three-passenger seat of a vehicle that can be separated into two seat sections, each independently slidable back and forth by means of a seat sliding rail defined by a pair of lower rails fixed to floor and a pair of upper rails fixed to the bottom of a seat. In the above-described seat belt mount mechanism, a seat belt of the center seating space of the seat is mounted to the inner upper rail of the respective seats.
The aforementioned seat belt mount mechanism requires sufficient distance between the right and left anchors of the seat belt of the center seating space of the seat, and the inner upper rail of the seat has to be arranged away from the center thereof. Therefore, the upper rails have to be positioned under the seats upon which the passengers of the right and left seating spaces are seated, resulting in deteriorated seating comfort. Furthermore, the resultant cantilever-like seat structure is likely to be affected by the moment exerted from the center seating space of the seat, so the structures of the seat and the upper rails are required to have sufficient strength.
Another type of seat belt mount mechanism, in which the anchors of the seat belt of the center seating space are mounted to the reinforcement provided between a pair of the upper rails via brackets has been proposed in order to arrange those anchors of the seat belt of the center seating space of the seat away from the center. This seat belt mount mechanism, however, may require an extra element for reinforcement. Moreover, the upper rails and reinforcement are required to exhibit enough strength to bear the bending moment generated by exertion of a high tensile load to the seat belt. The resultant seat belt mount mechanism may thus have heavy weight, leading to increased production costs.